Increases in the availability and usefulness of air travel for business and personal reasons have led to busier airports handling a larger number of airplanes landing in a smaller window of time. To provide clearance instructions, such as which runway to land on, air traffic control personnel must use a radio adapted to audibly send the instructions to an airplane flight crew. The flight crew must then manually program the clearances into a flight management system to receive further information, such as unique characteristics of a runway. Often, clearances are received very near landing, making manual entry highly inconvenient.
Instructions, informing a flight crew how closely to follow behind another plane, must also be provided by radio, and must be carried out by means of a pilot's own skill, visually judging the distance between the plane and the other plane to be followed by watching the other plane through the cockpit window. The only display panel provided by the airplane to the flight crew indicating a distance to the other plane is a Traffic Alert/Collision Avoidance System (TCAS) equipped to render a warning to the flight crew if a collision appears imminent.